Controlling mechanism for hydraulic presses and the like.



W. R. CLARK. EANISM FOR HYDRAULIC YRBSSES AND T APPLIGATION FILED JUNE?, 1912.

HE LIKE.

GONTROLLING MEG Patented July 14, 1914.

Pressure.

High Prgs are UNITED. sTATEs PATENT oEEioE.

WALTER R. CLARK, OF BRIDGEPORT, CONNECTICUT, ASSIG'NOR TO BRIDGEPORT BRASS v COMPANY, OF BRIDGEPORT, CONNECTICUT, A CORPORATION OF CONNECTICUT.

CONTBOLLING MECHANISM HYDRAULIC PRESSES AND THE LIKE.

Moscas.

Patented July 14, 1914.

Application filed June 7, 1912. Serial No. 702,275.

To all whom t may concern Be it-known that I, lVALTER R. CLARK, a citizen of the United States, ,residing in Bridgeport, county of Fairfield, and State of Connecticut, have invented certain new and useful Improvements -in Controlling Mechanism for Hydraulic Presses and the like, of which the following is a full, clear, and exact description.

This invention relates to controlling mechanism for hydraulic presses, draw benches, and other machinery operated by fluid pressure, and it refers especially to contro-lling mechanism for machines in which a ram or other moving part is arranged for operation by fluid under high pressure o-r fluid from a source of low ressure, or fluid from both high and low 'pressure sources. Usually, the reciprocating ram or other member ordil narily employed for acting on the work is actuated by low pressure until the tool meets the work, and then water under high pressure is permitted to act on the ram in order to perform the Working stroke, the return stroke being effected under low pressure. Ordinarily the low pressure water acts much more quickly than the high pres- .sure water, so that considerable time is saved by having the low pressure water` pro-duce lthe return stroke of the ram or other member and the idle portion of the operative stroke z'. c. that portion of the operative stroke which vprecedes the meeting of the tool with the Work.

The object of the invention is to provide a simple, eflicient system for automatically changing over from high to low pressure and vice versa in order to meet the above conditions.

.In a companion application, ASerial Number 70227 3, filed of even dateherewith, I

-have described and broadly claimed a system of control in which the high and low pressure sources for operating the prime mover are automatically and oppositely controlled by means actuated by a change'of .felocity of the liquid flowing through the system, which change of velocity is due to the retarding or acceleration ofthe moving element of the prime mover as such prime mover encounters more or less resistance. In the apparatus described 'in said companion application the motor device for actuating the valve of one of the pressure mains is actuated by variations in the pressure drop between the opposite sides of one or more orifices past which the fluid. flows at l one point in the system, which variations of pressure are directly due to the changes in the velocity of the fluid or liquid flowing through such orifice or orifices, According to the present invention, however, the variation of pressure for actuating the means for controlling one or more of the pressure conduits is not produced directly by the use of a restricted orifice or orifices, but-- is produced in another manner, to Wit, by means of a Venturi tube or so-called Venturi water meter arrangement.

The present invention is therefore an improvement or variation of that set forth in the aforesaid companion application, and

Venturi tube or its equivalent with the pres'- `sure mains of the system and the motor device for actuating one or more of the valves lin the mains, all as hereinafter described and claimed.

The invention further consists in certain details of the valve actuating motor device and other details of the apparatus as fully set forth hereinafter.

n the accompanying drawing, Figure 1 i is a diagrammatic view of the apparatus embodying vthe invention, showing the prime mover at the beginning of the stroke, Fig. 2

is a similar view, showingthe prime mover at the end of the stroke, Fig. 3 sho-ws a valve actuating motor device of slightly modified form, and Fig. 4 is a View similar to Fig. 3, but showing the parts in anothervposition.

Referring to the drawing, the prime mover A is shown as. comprisinga cylinder 10 in which a piston 11 is arranged to reciprocate. At one end of the cylinder is a port 12a connected by means of a pipe 15 with a fourway valve B. A port 13 at the oppositev end of the cylinder 10 is also in communication with this four-way valve B by means of a pipe 16. The four-way valve is adapted to place either port 12a or 13 in communication with vvan exhaust pipe 16a or with an inlet pipe 12 adapted to carry either high or low pressure Water or both to either end of the cylinder 10 and thereby actuate the piston 11 in either direction.

The high pressure main or conduit is connected with the casing of a motor device y carrying a piston valve E to be hereinafter described, and has a branch connection Cx leading from said casing to thejuiiction of the common inlet pipe 12 with the low pressure main D, which latter is provided in the rear of such junction with a suitable controlling valve F. In the embodiment' shown the valve Fis a spring actuated automatic check valve normally held in its open position by the force of the liquid flowing from the low pressure source,

but I do not limit myself to any specic form of valve.

In advance of the junction of the high and low pressure conduits C", D, with the common inlet pipe or conduit 12, the latter conduit is provided with a constricted portion G in the form of the well known Venturi tube. l The larger end of the Venturi tube thus formed is connected by means of a pipe 17 with a chamber 18 at oneend of the motor device E. This chamber 18 contains a pisrton 19 against which the liquid derived from the pipe 17 acts at one side, while the opposite side or face of the piston is acted upon by liquid derived from the intermediate constricted portion of the Venturi tube G by way of a pipe 20. Hence the arrangement is such that pressure transmitted from the larger cross-section of the Venturi tube'is imparted to the piston at one side while the pressure at the constricted portion of the Venturi `tube is transmitted to the'opposite side of the piston.

The piston 19 is provided with a piston rod 21 extending through the casing and 22 for controlling the high pressure water. This piston valve is arranged to slide with the piston through openings orseats in partitions or walls 23, 24, extending across the casing E. These partitions or walls form a chamber 25 in communication with the branch Cx of the high pressure conduit. The main high pressure conduit C leads into a chamber 27 partially separated from the chamber 25 by means of the partition 23, and it will therefore be understood vvthat when the piston valve 22 is moved out of the opening or seat 26 in said partition, communication will be established between the conduit C and the conduit C", as indicated by the arrows in Fig, 2. Within the chamber 27 is arranged a compensating or balancing piston 28 of slightly less area -than the piston valve 22, and as the high pressure water entering from the conduit C acts against this balancing piston in'v a direction opposite to that in which it acts upon the piston valve 22 the latter is partially balanced, as will be understood. A' spring 29 actin on the end of the piston rod 21 assists in hollding the piston 1 9 and the parts carried thereby normally in the position shown in Fig. 1 when low pressure Water is actin on the main piston 11.

The operation o the apparatus is substantially as` follows: Assuming the parts to be in the position shown in Fig. l, with low pressure Watei entering the main cylinder 10 by Way of the common inlet pipe or conduit 12, the piston 11 of the prime mover Will be thrust toward the right by the low pressure water.v This action will be continued as long as the resistance does notincrease materially, but when a material increase of resistance does occur, by the meeting of the tool of the press or the like with the work to be operated upon, the velocity of the low pressure Water flowing into the prime mover through the pipe 12 Will be reduced in correspondence with the retarding of the prime mover piston 11, thereby causing the motor device E to be koperated to open the high pressure valve 22. With a considerable velocity of flow through the inlet pipe A12 and the Venturi tube G thereof, i the velocity of the liquid passing through the constrictedl intermediate portion of the left of said liquid in the Venturi tube will be considerably greater than that of the liquid passing through the' end of the Venturi tube portion, as is well understood. With a considerable difference in velocity, there Willbe a considerable difference in pressure as between the restricted portion 'of the Venturi -tube and the unre-l stricted end or ends ofthe same, and therefore the pressure at the right of the piston 19.will be very much higher than that at the pipe 12 decreases, however, the pressure at the restricted portion of the Venturi tube tends to become more nearly equal to that of the unrestricted portion of the Venturi tube, and hence the pressure in the space at the left hand side of the piston 19 increases suiiiciently to overcome the opposing forces acting 0n the piston and to thrust the latter toward the right. This movement of the piston 19 and the parts carried thereby will cause the piston valve 22 to uncover ,the seat 26, as shown in Fig. 2, thereby opening the high pressure main'and permitting high pressure water to flow from the same through the branch or conduit X and into the inletv pipe 12. A portion of this high pressure water passes back to the valve F of the `low pressure main and closes said valveI against the low pressure Water thereby cut- .ting` oii' the lo-W pressure' liquid, andthe remainder of the high pressure liquid passes to t-he vmain cylinder 10 through the pipe 12 .to commence and completethe Working portion of the stroke. It will be understood that the same operatic-ns will Y take place when the piston 11 is reversed by means of the four-Way .valve B. When there is no material resistance to the movement of the piston, ther-vater passing to the cylinder 10 by Way of the pipe 12 attains such a high velocity that the pressure at the restricted portion of the Venturi4 tube is suiiiciently piston. As the velocity of the loof low to permit the high pressure valve 22 to be closed by the forces urging the piston 19 toward the left, and said high pressure valve is only opened when the prime mover piston l1 is so retarded as to increase the pressure at the restricted portion ofthe Venturi tube to a predetermined extent, as before eX- plained. It will therefore be understood that the Venturi tube forms a simple and eflicient means for producing considerable pressure variations for actuating the valve operating motor device as the velocity of the liquid in the system fluctuates.

In Figs. 3 and 4 I have shown a modified forni of valve actuating motor device, denoted by reference character E. vIn this instance, a diaphragm 30 is used instead of a piston, the pipes-31' and 32 from the restricted and unrestricted po-rtions of the Venturi tube G being connected with spaces at opposite sides of this diaphragm. rlhe diaphragm is connected with a rod 33 ca'rrying an ordinary reciprocating valve 34 cooperating with :i seat 35 to control the flow of high pressure water through the two adjacent chambers of the casing. The opera.- tion of this device is substantially the same as that previously described and need not be referred to in detail..

.It will be understood that while the foregoing description is a detailed one in so far as it concerns the particular embodiment of my invention selected for illustration, vari-4 ous changes may be made in the apparatus without departing from the scope ofthe invention.

I have used the term Venturi tube hereiii and 'in the claims in its broad sense, intending to cover any device by means of which the well known Venturi effect is produced. Manifestly it is not necessary to locate the Venturi tube in the inlet conduit of the system in all cases; in some cases it may be placed in the exhaust conduit with equal advantage.

I do not claim herein the general combination, as set forth in my companion application Serial No. 702,273, of a prime mover, a source of motive fluid under high pressure. a source of motive fluid under low pressure, means connecting said sources with said prime mover, and means actuated by a decrease in the velocity of the fluid flowing through the system, due to an increase in the resistance encountered by the prime mover, to cut off the low pressure source from said prime mover and cut in the high pressure source. Neither do I claim such a combination in which the last named means includes a motor operated by variations of pipe friction pliczit'ion filed of even date herewith Serial No. 702,274. t

W'hat I claim is: 1. In controlling mechanism for hyas set forth in my other companion apdraulic `presses andthe like, the combination with a prime mover, of a usource of` higli fluid pressure -to operate said prime mover, a second source of fluid pressure of less dcgree than the first but likewise capable of operating said prime mover, means connecting said sources with said prime mover;l and `means including a Venturi tube located at one point in the system to cut off the low pressure source from said prime mover and cut in the high pressure source; substantially as described.

2. In' controlling mechanism for hydraulic presses and the like, the combination with a prime mover, of a source of high fluid pressure to operate said prime mover, a second source of fluid pressure of less degree than the first but likewise capable of operating said prime mover, a conduit connecting said sources with said prime mover, and means including a Venturi device in said conduit to cut off the low pressure source from said prime mover and cut in the high .pressure source as the resistance to the prime vmover increases; substantially as described.

3. In controlling mechanism for hydraulic presses and the like, the combination o-f a prime mover, a conduit connected with said prime mover to vsupply the same with high pressure motive fluid, a second conduit connected with said prime mover to supply the same with motive'fluvid under lower pressure but which is likewise capable of operating said prime Inover,`, said low pressure source being in communication with saidprime mover under ordinary conditions for operating the same, and automatic means includinga Venturi device located at one point in the system for cutting outlthe low pressurevsource and cutting in the high pressure source when the prime mover encounters a predetermined amount of resistance; substantially as described. l

4. In controlling mechanism for hydraulic presses and the like, the combination of a prime mover, a high pressure conduit, a low pressure conduit, ay common supply conduit connecting both of said first named conduits with said prime mover and having a Venturi portion therein, a valve for one of said conduits, and a fluid pressure motor for said valve connected with the Venturi portion of said common supply conduit; substantially as described.

5. In controlling mechanism for hydraulic presses and the like, the combination of a prime mover, a high pressure conduit.' a low pressure conduit, a common supply conduit connecting both of said first named conduits with saidprime mover, a valve for controllingv said high pressure conduit, a fluid operated motor device for said valve lcomprising a piston and a casing therefor,

ist

v inlet pipe; substantially as prime mover, a source stricted portions respectively of said common supply conduit; substantially as4 described.

6. The combination of a prime mover, a high pressure main, a 10W pressure main, a pipe connecting said mains With said prime mover and having a Venturi tube therein, and means actuated by varying pressure differences produced by said Venturi tube, as the velocity of the ingoing liquid changes, to control positively the flow of liquid through one of said mains; substantially as described.

7. The combination of a prime mover, a high pressure main, a low pressure main, a common inlet pipe having a Venturi tube portion, a valve 4for controlling the high pressure main, avvalve for controlling the 10W pressure main, and a motor device for at least one ofsaid valves, connected with said Venturi tube portion of the common described.

8. The combination of a prime mover, a high pressure main, 'a low pressure main, valves for controllingr an inlet pipe from said mains to said prime mover, having a restricted portion therein, and a motor device for the high` pressure valve,'having a casing connected at one point With the restricted portion of 'said inlet pipe, and connected another portion of as described.

9. In controlling mechanism for hydraulic l presses and the like, the combination of a to operate said prime mover, a second source of pressure fluid of less degree than the first the respective mains,

at another point With the system; substantially of high pressure fluid,

but likewise capable of operating said prime mover, means connecting said sources with said prime mover, and means actuated by a decrease in the velocity of the Huid iowing due to an increase in the resistance encountered by the prime mover, to cut orf the 10W pressure source from said prime mover and to cut in the high pressure source, said last named means comprising a motor device having acasing, a

movable valve actuating member in said casing, and a Venturi tube located at a suitable' point in the system 'and connected with said ca sing; substantially as described.

l0. In controlling mechanism for hydrauv lic presses and the like, the combination of a prime mover, a high pressure conduit, a low 'pressure conduit, means'to connect said conduits with 'said prime mover, a valve to control one of said conduits, and means to open said valve by a decrease in the velocity of the fluid flowing through the system, due to an increase in the resistance encountered by the prime mover, said 4last named means comprising a motor'device having a casing, a valve actuating element movable in said casing, a Venturi tube through which the liquid flows in the normal operation of the prime mover, and means connecting said Venturi tube with said casing; substantially as described. l

In Witness whereof, I have hereunto set my hand on the 5 day of June, 1912.

WALTER R. CLARK.

l/Vitnesses: l

JOSEPH B. HARRIS, RONALD G. HANDS.' 

